Gooch said she raised $100,000 in the three days before her Wednesday night announcement, with the donations coming primarily from individual donors who live in Southern California.

“I knew that it was important that I demonstrate viability before I made my announcement,” Gooch said. “I see a path to victory. … I have to tell you, my supporters are a bipartisan group of supporters. If you look at who I am, I am not a politician. I am someone who likes to get things done.”

Gooch also touted an early endorsement from Miller, for whom she worked on Capitol Hill from 2003 to 2007 before leaving for the lobbying firm Potomac Partners. After a three year stint as a lobbyist, she rejoined Miller’s office in 2011.

Gooch says she made the decision to run for the seat in her home district just days after Miller announced his retirement and consulted with him before announcing her candidacy.

“She is a great candidate for the district. She has 15 years of experience on the Hill. I think she is going to be the frontrunner on the Republican side for sure,” Miller told POLITICO Thursday. “I think she’s absolutely the most qualified.”

Gooch enters the race against just two other GOP contenders, retired Navy officer Paul Chabot and San Bernardino Councilman John Valdivia. Because of California’s open primary system, however, she will also compete against three Democratic candidates: former Rep. Joe Baca; Emily’s List-backed Eloise Gomez Reyes; and Democratic Congressional Campaign Committee favorite Pete Aguilar.

The two candidates who receive the most votes in the June 3 primary, regardless of party affiliation, will move on to the general election.

While Gooch’s early fundraising numbers give her candidacy some muscle, any Republican hopeful faces an uphill battle in the 31st district, where President Barack Obama won by a 16 point margin in 2012 and 2008. In fact, Miller’s seat is seen as perhaps Democrats’ best chance of picking up a Republican seat.

Democrats intend to paint Gooch as a Washington insider, citing her career on Capitol Hill and, since 2007, her work as a lobbyist for the firm Potomac Partners. And her fundraising might serve to draw attention to her ties to Washington.

“It’s no surprise that somebody who used to work for an incumbent like Rep. Gary Miller, somebody who has deep connections to special interests, is able to tap into that same network to raise campaign funds,” said Tenoch Flores, communications director of the California Democratic Party.

Miller rejected that characterization, pointing to the Democratic Congressional Campaign Committee’s backing of Aguilar and Emily’s List’s support for Reyes to make the point the Democratic candidates in the district are receiving money from outside the state.

“The difference is that Leslie is going out and raising this money herself, where others are having the money raised for them,” Miller said. “I have not made one fundraising call for her. She has done this solely on her own.”

Gooch also defended her career in Washington, emphasizing that she knows the way the Capitol works and has used that to advocate for her home region.

“I have worked my entire career on behalf of the Inland Empire. I was born and raised here and I want to give back to this community,” she said. “People say Washington is broken. Yes, it is. But we need to fix it with people who know how it works.”

Democrats remain confident they will flip the seat in November.

Aguilar is “someone the community knows well and has responded to. He’s raising the cash you need to compete in that area,” said Tyrone Gayle, regional press secretary for the DCCC. “Congressman Miller’s extreme policy positions on immigration reform, the Ryan Budget plan, and women’s issues are precisely why he couldn’t win reelection in the first place so it’s hard to imagine his top policy adviser being a viable candidate.”

Miller isn’t convinced.

“I don’t believe the district is going to a Democrat. I know the district,” he said. “They said when I ran two years ago that it was going to go Democrat and it didn’t go that way at all.”